At around 06:30 hrs on Sunday 28 May 2017, a trailer, being propelled by a small rail tractor between Edale and Bamford, became detached and ran away for a distance of around 1 mile (1.6 km). It came to a stop at a set of points at Earles Sidings, near Hope. There were no injuries that required medical attention, and there was no significant damage to the infrastructure, the trailer or the tractor.
The tractor and trailer became separated because the towbar pin fell out. A linch pin that secured the towbar pin had almost certainly been inserted in the wrong orientation. This would have resulted in it falling out, allowing the towbar pin to fall out and the towbar to become uncoupled.
The subsequent runaway occurred because the brakes on the trailer had been manually disabled by the staff present, to overcome them being stuck in the applied position. It is likely that this was because the hydraulic brake hose between the tractor and the trailer had either been not connected or incorrectly connected at the start of the shift.
The RAIB has made three recommendations to Network Rail as a result of this investigation. One relates to providing staff with guidance on what actions to take if a trailer becomes immobilised when being used. The second relates to management of staff competence at the depot involved in the incident. The third relates to learning lessons from multiple non-compliances during use of the plant.
The RAIB has also identified two learning points, relating to the precautions required when isolating trailer brakes and to the requirements to carry out a full set of brake tests prior to use.
Published 19 February 2018